In a move that could have led to the collapse of the government coalition, Green Party chairman and finance spokesperson Dan Boyle last week offered his resignation to party leader John Gormley.

The senator's dramatic move came in the wake of the government announcement of its banking inquiry.

Mr Boyle, who played a pivotal role in the renegotiated Programme for Government, was upset and dismayed at Taoiseach Brian Cowen's statement that a major part of the banking inquiry's work would be held in private.

It is understood Mr Gormley urged the senator to reconsider his resignation, given the potential fall-out from such a move. In a further twist, there has been deep anger among Green Party faithful over leaks to the Irish Times suggesting that the Government wanted to nominate Mr Boyle to the European Court of Auditors.

Such a move would effectively remove the senator from the Irish political scene.

After Mr Cowen announced details of the inquiry, Mr Boyle offered his resignation.

Mr Gormley urged the Cork-based senator not to make a move that potentially would have left the party with little alternative but to step out of Government.

A party source said Mr Boyle's anger stemmed from the fact that he believed the inquiry needed to have a major public element to it.

The Government's Banking Inquiry Bill provides for a number of scoping exercises and two separate inquiry strands which will be held in private. Mr Cowen has insisted that there will be a public element when the Oireachtas debates the findings.

But the senator believes that for the inquiry to have the trust of the people, it has have a more substantial public element to it.

Speaking on my Newstalk Lunchtime Show on Friday, Mr Boyle said he would look favourably on Mrs Justice Catherine McGuinness's proposal for a more open form of inquiry.

When contacted yesterday morning, he revealed that his resignation move was driven by his deep unease with his coalition partners' handling of the inquiry. He said: "After the first six months of 2009, we thought the business of government might become more comfortable. This is hardly an ideal start to the year."

While he refused to comment further on the matter, it is believed that he reconsidered his resignation on the basis that the Green Party could achieve amendments to the proposed legislation.

In a further blow to the Coalition's unity, there is widespread anger among Green members over a story leaked to the Irish Times which suggested Mr Boyle might be nominated to the European Court of Auditors by the Taoiseach.

A party source said this could be seen as an attempt by the Taoiseach to muzzle the outspoken senator. Mr Boyle refused to comment on this issue but it is understood he will not be moving to Europe anytime soon.